<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .container {
            display: table;
            width: 600px;
            height: 600px;
            background-color: silver;
        }

        /* 虽然垂直居中 但充满了父元素*/
        .content {
            display: table-cell;
            vertical-align: middle;
            width: 200px;
            height: 200px;
            background-color: navajowhite;
        }
    </style>
</head>
<body>
<div class="container">
    <div class="content">
        hello world my name is my
        hello world my name is my
        hello world my name is my
        hello world my name is my
        hello world my name is my
        hello world my name is my
        hello world my name is my
    </div>
</div>
</body>
</html>
